The team completed their first comprehensive performance test a few hours early on observatory number one, an indication that no significant issues were encountered.

This summer, they expect to start environmental testing, which ensures the spacecraft can withstand the extreme conditions of space. Technicians are working to integrate components on the remaining three observatories. Due to launch in late 2014, MMS will investigate how the sun and Earth's magnetic fields connect and disconnect, explosively transferring energy from one to the other – a fundamental physical process that occurs throughout the universe, known as magnetic reconnection.